To study the effect of double circular holes on the mechanical properties of rocks and the crack extension process, a uniaxial compression model for rock specimens containing double circular holes was constructed, and the correctness and rationality of the numerical model were verified based on the comparison of the macroscopic mechanical parameters obtained from experiments and simulations. In addition, the crack extension process of specimens containing double circular holes and the evolution of the stress field around the circular holes were analyzed. The results show that the numerical simulation results are in good agreement with the experimental results;the initial tensile crack first sprouts at the upper and lower ends of the circular hole, and with the increase of axial stress, structural weak zones are usually formed at the left and right sides of the hole wall. The sprouting direction of the initial tensile crack is in the axial load-ing direction, independent of the orientation angle α, but the damage pattern of the specimen is influenced by the orientation angle α. The initial tensile crack is generated in the tensile stress concentration area;the tensile stress concentration area at the upper and lower ends of the circular hole moves and dissipates accordingly with the expansion of the initial tensile crack. The compressive stress concentration area of the stress component σyy is located on the left and right sides of the circular hole, while a shielding area of compressive stress is formed at the upper and lower ends of the circular hole, and the smaller the distance from the vertical center line of the circular hole, the stronger the shielding effect and the weaker the compressive stress.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |